This invention relates to electric toothbrushes, sometimes referred to as mechanical toothbrushes, and is more particularly directed to a portable hand-held, electrically powered, mechanical toothbrush. Specifically, a novel toothbrush head is disclosed.
The use of manual toothbrushes has, of course, been know for many years. Indeed, the use of mechanical toothbrushes, typically those which are electrically driven, has been known for a number of years. The purpose, in any event, is to clean the teeth, usually with a toothbrush which comprises a plurality of bristles that are used in conjunction with a dentifrice. Very often, the dentifrice is mildly abrasive.
The dental profession has propounded, for many years, a technique known as the xe2x80x9cBass Techniquexe2x80x9d which, if properly performed, is said to achieve superior results in terms of cleaning one""s teeth using a manual toothbrush. Essentially, the Bass Technique requires the user to position a manual toothbrush over a zone of the teeth, and then to use very short stokes so as to more or less vibrate the brush at that zone where the brush has been located. This short-stroke brushing should continue for a period of timexe2x80x94typically, twenty strokes to forty strokesxe2x80x94so as to remove any foreign material from that zone. The brush is then repositioned and typically another twenty to forty short strokes are performed. Because each zone is very small, the Bass Technique can be very time consuming. Moreover, since it is a requirement that the strokes be very short which, in turn, requires excellent muscle control, exercising the Bass Technique can be very tiring.
The theory is that, at the end of any given stroke, the bristles will flex so as to become oriented in such a manner that the ends of the bristles point generally away from the direction of the travel of the bristles across the teeth. However, at the beginning of the next stroke, in the opposite direction, the still-flexed bristles will then be pointed in the direction of the stroke and this may cause the bristle to chisel the foreign material away from the teeth for a moment before the bristle again begins to flex so as to sweep across the surface of the tooth in the zone where it is located.
However, a more efficacious manner for brushing teeth comprises a variation of the Bass Technique, whereby oscillatory movement is imparted to a toothbrush. Of course, such oscillatory movement is not capable of being executed manually.
A purpose of the present invention is to provide an electromechanical toothbrushxe2x80x94that is, an electrically driven, mechanical toothbrush, most typically referred to as an electric toothbrush which will permit the user to perform a tooth cleaning procedure which improves upon the Bass Technique by imparting oscillatory movement to the toothbrush. In other words, by using the toothbrush of the present invention, the user will be able to locate the toothbrush at a given zone for a short period of time, while executing a plurality of oscillatory motions of the toothbrush to clean the teeth, and then move on to the next zone, thus achieving efficient cleaning of the teeth.
Apart from the removal of leftover food particles and the like, a particular purpose for cleaning the teeth is to remove plaque build-up from the teeth. Typically, when using a manual toothbrush, plaque build-up is removed much more easily from the buccal surfaces of the teeth than from the lingual surfaces of the teeth, with relatively good foreign material removal from the occlusal surfaces of the teeth also being achieved.
One development that has occurred in respect of manual toothbrushes is the provision of twin-headed brushes, whereby the lingual and buccal surfaces of the tooth can be scrubbed using the bristles of the brush at the same time, with the same stroking action of the brush.
As to electric toothbrushes, most electric toothbrushes provide groups of bristles which are located in concentric circles, where the brush head thus provided is rotated or, more usually, it is reciprocally rotated. The co-pending application noted above teaches a toothbrush having twin heads to which a lengthwise reciprocating linear motion is imparted.
Several typical prior art toothbrushes are now described. Among them are several manual toothbrushes which comprise dual, opposed bristle heads. They include PORPER U.S. Design Pat. No. D259,977, issued Jul. 28, 1981, which reveals an early design for a toothbrush having opposed bristle heads.
Another manual toothbrush which is adapted for cleaning multiple sides of the teeth at the same time is shown in WAGNER U.S. Pat. No. 5,327,607, issued Jul. 12, 1994. The toothbrush disclosed in that patent includes further bristles which extend from the spine of the toothbrush so as to contact the occlusal surfaces of the teeth at the same as the buccal and lingual surfaces of the teeth are being contacted while the toothbrush is in use.
A typical prior art electric toothbrush is disclosed in AMAKASU U.S. Pat. No. 5,359,747, issued Nov. 1, 1994. Here, a brush member of the toothbrush is given reciprocal motion in the axial direction while, at the same time, the brush member itself is given a rotary motion. The rotary brush member is rotatably mounted on the end of an attachment connected to a drive shaft, and the reciprocating motion in the axial direction thereof is converted into a rotary motion and transmitted to the rotary brush member by a second transmission mechanism.
Another typical prior art electric toothbrush is disclosed in BAUMAN U.S. Pat. No. 5,353,460, issued Oct. 11, 1994. Here, there is a pair of brush elements with driving mechanism which drives one of the brush elements in oscillation, with linkage between the brush elements so that the second brush element is also driven in oscillation. The two brush elements are preferably oscillated in opposite directions. However, the two brush elements can only contact any one surface of the teeth at a time.
A mechanical toothbrush which is said to effectively replicate the Bass Technique is STANSBURY U.S. Pat. No. 5,259,083, issued Nov. 9, 1993. This power driven mechanical toothbrush comprises a plurality of tuft blocks which are mounted on a cam shaft. The tuft blocks are received in sliding relation in a toothbrush head member, and each tuft block slides linearly in a direction parallel to the longitudinal tuft axis as it is guided by guide rails within the head member between a retracted position and an extended position. The tuft blocks are each driven by the rotatable cam. In use, the tuft bristles are brought into contact with the teeth by the user, before the respective tuft block reaches its extended position, so as to thereby flex the bristles and to cause a lateral motion of the distal end of the bristles along the surface of the teeth. This whipping action of the ends of the bristles causes a wiping action across the surface of the teeth while, at the same time, causing a chiselling action by the ends of the bristles against the teeth, so as to thereby remove foreign material away from the teeth in the region where the bristle chiselling action occurs.
Finally, DAUB U.S. Pat. No. 5,027,463, issued Jul. 2, 1991, teaches a toothbrush which may be used for simultaneously brushing and cleaning the occlusal, lingual, and buccal surfaces of the upper and lower teeth of the user. Here, a bristle support member is provided which anchors bristles which extend from the opposite surfaces thereof. The bristles are arranged so that the central rows of bristles are straight while the intermediate and outer rows of bristles on each of the opposed surfaces of the bristle support member are curved. The straight bristles will engage the occlusal surfaces of the teeth, while the intermediate and outer rows will engage the lingual and buccal surfaces of the teeth.
In accordance with one aspect of the present invention, there is provided an electric toothbrush which comprises a power handle portion and a brush head portion. The power handle portion is adapted to provide a housing for an electric motor and for a driving mechanism which is located at a first end of the power handle portion.
The driving mechanism is powered by the electric motor, and the electric motor has a longitudinal axis. The brush head portion of the toothbrush also has a longitudinal axis which is offset by a first offset distance with respect to the longitudinal axis of the electric motor.
The brush head portion of the toothbrush of the present invention is removably attachable at a first end thereof to the first end of the power handle portion, and the brush head portion comprises a pair of opposed bristle head portions arranged so as to present two groups of opposed bundles of bristles disposed substantially perpendicularly each to the other. Each of the groups of bundles of bristles on each respective bristle head portion comprises a plurality of rows and a plurality of columns of bristle bundles, where the rows of bristle bundles are aligned parallel to the longitudinal axis of the brush head, and the columns of bristles are aligned perpendicular the longitudinal axis of the brush head.
The bristles in each bundle in each row of bristle bundles on each bristle head portion are substantially equal in length. The length of the bristles in the respective row of bristle bundles on each bristle head portion which is closest to the longitudinal axis of the brush head portion is shorter than the length of the bristles in the respective row of bristle bundles on each bristle head portion which is furthest away from the longitudinal axis of the brush head portion. Moreover, the lengths of the bristles in each respective row of bristle bundles on each bristle head portion are progressively longer in each row of bristle bundles which is further away from the longitudinal axis of the brush head portion than an adjacent row of bristle bundles which is closer to the longitudinal axis of the brush head portion.
Typically, the outer ends of the respective row of bristle bundles which is closest to the longitudinal axis of the brush head portion, on each of the bristle head portions, are spaced less than 0.100 inch from the outer ends of the respective opposed row of bristle bundles on the other bristle head portion.
The driving mechanism of toothbrushes in keeping with the present invention comprises a motion translation means for translating rotational driving power from the electric motor to oscillatory motion delivered to the brush head portion. The driving mechanism further comprises a drive shaft which is disposed on the longitudinal axis of the brush head portion of the toothbrush. The drive shaft is adapted to deliver oscillatory driving power from the motion translation means to the brush head portion.
The drive shaft of the driving mechanism is received in a socket in the brush head portion of the toothbrush of the present invention, in a manner so as to receive the drive shaft in position along the longitudinal axis of the brush head portion.
Accordingly, rotational motion of the flywheel is translated by the motion translation means into oscillatory motion of the drive shaft, so as to provide oscillatory movement to the pair of opposed bristle head portions of the brush head.
In keeping with a particular feature of the present invention, as described in greater detail hereafter, the brush head portion comprises two matched halves, and the drive pin. Each of the two matched halves comprises a respective one of the bristle head portions and a respective half of an intermediate arm portion of the brush head portion. Each respective matched half is formed with a portion of the socket at the first end thereof. The socket portion is disposed on the longitudinal axis of the brush head portion. As noted, the drive shaft is received in the socket so that oscillatory driving motion is directly transmitted to the brush head portion.
A further aspect of the present invention is to provide such an electric toothbrush as is described above, where the brush head portion further comprises a collar portion at the first end thereof, which collar portion is adapted to be removably attachable to the first end of the power handle portion. The opposed bristle head portions of the brush head portion are disposed at the end of an intermediate arm portion thereof, which end is opposed to the first end of the brush head portion. The intermediate arm portion is accommodated within the collar portion in such a manner that the drive shaft is received in the socket while being maintained in position on the longitudinal axis of the brush head. This permits replacement of the brush head by a new brush head, or by a different brush head for use by a different user of the toothbrush mechanism of the present application.
A purpose of the present invention is to provide such an electric toothbrush as described above, which can be used to effectively impart the improved version of the Bass Technique to the toothbrush heads and, thereby, to achieve better tooth cleaning results.
Finally, a purpose of the present invention is to bring an electric toothbrush to the market which can be used for very effective cleaning of the teeth, but which can be brought to the market at relatively low cost compared with many of the prior art electric toothbrushes, due to the relatively uncomplicated structure of the electric toothbrush hereof.